Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 050349 AFDCTP Area Forecast Discussion National Weather Service State College PA 1049 PM EST Thu Mar 4 2021 .SYNOPSIS... An upper trough will deepen over the northeast CONUS into the upcoming weekend, then be replaced by an anomalous upper level ridge over the east coast that will bring warming temperatures during the first half of next week. A weakening cold front could approach the region late next week. && .NEAR TERM /UNTIL 7 AM FRIDAY MORNING/... For the rest of the overnight, much drier and very low dewpoint air of -25 to -40C at 850 mb (that caused the quick cloud dissipation from north to south earlier this evening), will extend across most of the CWA. This will maintain clear to partly cloudy skies across the region with a moderately gusty NW wind into the mid teens to low 20s (KTS) at times. Low temps tonight will vary from 10 to 15 across the north to around 20F in the Southern Valleys. Wind chills will range from zero to 5 below zero F across the Northern Mtns to the single digits above zero elsewhere. && .SHORT TERM /7 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... The tight pressure gradient between a ridge over the midwest and an intense low over the Canadian Maritimes will result in a brisk northwest flow over PA. The low subsidence inversion height and generally dry air should result in minimal lake effect clouds over the majority of the CWA. But, the western mtns will not be so sunny, esp in the NW as the day goes on, thanks to lift from the mtns, moisture from the lakes and a channel of potent vorticity aloft. Maxes will be 1-5F cooler than Thursday, running between u20s and 40F. && .LONG TERM /SATURDAY THROUGH THURSDAY/... An amplifying upper trough will develop from the Canadian Maritimes to the Central Appalachians Saturday afternoon through Sunday, followed by quickly rising heights/thickness values early in the upcoming week. Saturday and Sunday will be equally cold for early March days, and although there will be a fair amount of vertical shear and relatively shallow moisture, the dendritic growth zone will reside within the low cloud layer, so periods of flurries and maybe even a ground whitening of snow could occur across the higher terrain of NW PA and the Laurels. However, most of Lake Erie is covered with ice, so we`re not expecting much snow if LES generates Saturday and Sunday. In the big picture, our ensemble prediction systems have remained consistent of late, showing a significant warming for next week, as a deep eastern Canadian vortex fills and shifts into the north Atlantic. This will allow ridging to push towards the eastern CONUS, with our low-level flow backing into the W and SW, heralding the arrival of Spring- like temperatures (highs ranging from the 50s-mid 60s by the middle of next week). Although much of this time frame looks dry from this early vantage point, both moisture and model uncertainty look to be on the increase towards the end of the forecast period (late Wed. onward), so the threat of showers could be looming by that time. Overall, though, the main theme is for a trend towards pleasant, early Spring type weather from Mon. through Wed. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Generally VFR ceilings will continue to scour out across central PA due to the combo of sinking/drying air under high pressure and the dry well-mixed low levels. West/northwest winds will remain gusty all night (10-15G20-25KT), and even pick back up a bit on Friday. Outlook... Sat-Sun...Occasional MVFR clouds NW, otherwise gusty W-NW wind. Mon-Tue...Occasional MVFR clouds NW, otherwise no sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/Fitzgerald NEAR TERM...Lambert/Dangelo SHORT TERM...Lambert/Dangelo LONG TERM...Jurewicz/Lambert/Wagner AVIATION...Guseman/Dangelo

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